Naan Avanillai (transl. I am not him) is a 1974 Indian Tamil-language film starring Gemini Ganesan. Produced by Ganesan himself, it was written and directed by K. Balachander. The film is based on the 1962 Marathi language play To Mee Navhech, written by Pralhad Keshav Atre. It deals with a man who woos and marries several women while he takes on as many different identities.

Naan Avanillai was released on 7 June 1974. The film was commercially successful and received critical acclaim. Ganesan's won the Filmfare Award for Best Actor – Tamil. It was later remade into a 2007 Tamil film with the same title and a 2008 Kannada film titled Buddhivantha.